His intervention came after Guy Verhofstadt, the European Parliament's Brexit coordinator, told British Prime Minister Theresa May to offer greater concessions to the EU and outline what sort of trade deal she wants, following talks at a Brussels summit.
European Union leaders threw May a lifeline in Brexit talks on Friday, agreeing to start preparations for the next stage of negotiations on post-Brexit trade and a transition deal.
European capitals are demanding detailed written commitments on the divorce bill from London before consenting to the start of trade talks, fearing that Britain's departure in 2019 will blow a hole in the bloc's budget.
"In other words, how much does the European Commission and the European elite want to punish Britain for having the audacity to use our legal rights to leave?" he told ITV television.
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Fox said prosperity on the continent should come before the EU's drive towards ever-closer union, which he said had reached "a near-theological level".
He said there could not be a final divorce bill until Britain knew what it was getting in return in terms of free trade.
Verhofstadt said May should call the bluff of the "increasingly desperate Brexiteers" and "outline, once and for all, what kind of future relationship the country wants".
"Brexiteers failed to outline the extent of UK liabilities in Europe. Nevertheless, what is clear is that it will not be the taxpayers of the European Union who pay Britain's bar bill."
May is expected to update parliament on the summit outcome tomorrow.
She was to reaffirm her commitment to the three million EU nationals living in Britain who make an "extraordinary contribution", saying "we want them to stay".
"The negotiations are complicated and deeply technical but in the end they are about people -- and I am determined that we will put people first," she was to say.
Britain's Brexit Secretary David Davis is due to travel to Paris for talks tomorrow, after French President Emmanuel Macron suggested at the summit that London would need to ramp up its divorce payment offer to unlock trade negotiations.
Davis is due to have dinner with French Foreign Minister Jean-Yves Le Drian.
"Labour will work with all sides to make that happen," said shadow Brexit secretary Keir Starmer.